Inner fixed structure leading edge latch

ABSTRACT

Pin latch assemblies and cam latch assemblies are disclosed. A pin latch assembly is provided comprising a pin housing at least partially enclosing a pin, an actuating device coupled to the pin, and a retaining feature comprising an aperture.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of, and claims priority to, and thebenefit of U.S. Non-Provisional application Ser. No. 14/672,193,entitled “INNER FIXED STRUCTURE LEADING EDGE LATCH,” filed on Mar. 29,2015, which is hereby incorporated by reference in its entirety.

FIELD

The present disclosure relates to latch assemblies capable of being usedin an aircraft nacelle, and more particularly to a latch between theleading edge of an inner fixed structure of a propulsion system thrustreverser and the engine case.

BACKGROUND

A bypass duct of a nacelle may be disposed about a gas turbine engine.The bypass duct may be at least partially defined by an inner fixedstructure (IFS) of a thrust reverser. Under certain conditions, anoverpressure event underneath the IFS may cause the IFS to deflect in aradially outward direction with respect to the gas turbine engine. Ifthe leading edge of the IFS deflects enough into the bypass duct, itwill begin to scoop the high velocity air within the duct, which willresult in a further increase of forces and additional deflection. Suchdeflection, if extreme, may damage the IFS and jeopardize its integrity.

SUMMARY

Pin latch assemblies and cam latch assemblies are disclosed. A latchassembly located between a leading edge of an inner fixed structure(IFS) and an engine case is provided comprising a moveable portion, ahandle, a receiver, wherein the latch assembly is configured to be in alatched position when the moveable portion is located within thereceiver, wherein the receiver and the moveable portion comprise awaiting-fail-safe load path when in the latched position, wherein thehandle is coupled to a fan case, wherein the handle is coupled to themoveable portion via a flexible cable, wherein the flexible cable isrouted through a guide vane, the guide vane being located between theengine case and the fan case.

A latch assembly located between a leading edge of an inner fixedstructure (IFS) and an engine case is provided comprising a moveableportion, a handle, a receiver, wherein the latch assembly is configuredto be in a latched position when the moveable portion is located withinthe receiver, wherein the receiver and the moveable portion comprise awaiting-fail-safe load path when in the latched position, wherein themoveable portion is remotely actuated by a flexible cable, wherein theflexible cable is toured through a guide vane between the engine caseand a fan case.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter of the present disclosure is particularly pointed outand distinctly claimed in the concluding portion of the specification. Amore complete understanding of the present disclosure, however, may bestbe obtained by referring to the detailed description and claims whenconsidered in connection with the drawing figures, wherein like numeralsdenote like elements.

FIG. 1A illustrates a schematic view of a gas turbine engine, inaccordance with various embodiments;

FIG. 1B illustrates a schematic view of a gas turbine engine attached toa pylon, in accordance with various embodiments;

FIG. 2A illustrates a cross-sectional view of the gas turbine enginetaken along line 2-2 in FIG. 1A and under normal operating conditions,in accordance with various embodiments;

FIG. 2B illustrates a cross-sectional view of the gas turbine enginetaken along line 2-2 in FIG 1A and under an overpressure event, inaccordance with various embodiments;

FIG. 3A, illustrates an isometric view of an exemplary pin latchassembly in the closed position, in accordance with various embodiments;

FIG. 3B illustrates an isometric view of an exemplary pin latch assemblyin the open position, in accordance with various embodiments;

FIG. 3C illustrates a side view of an exemplary pin latch assembly inthe closed position, in accordance with various embodiments;

FIG. 3D illustrates a side view of an exemplary pin latch assembly inthe open position, in accordance with various embodiments;

FIG. 4A, illustrates an isometric view of an exemplary cam latchassembly in the closed position, in accordance with various embodiments;

FIG. 4B illustrates an isometric view of an exemplary cam latch assemblyin the open position, in accordance with various embodiments;

FIG. 4C illustrates a side view of an exemplary cam latch assembly inthe closed position, in accordance with various embodiments;

FIG. 4D illustrates a side view of an exemplary cam latch assembly inthe open position, in accordance with various embodiments;

FIG. 5A illustrates a latch handle assembly with cable placement, inaccordance with various embodiments;

FIG. 5B illustrates a latch handle security device with a fan cowl inthe closed position, in accordance with various embodiments;

DETAILED DESCRIPTION

The detailed description of exemplary embodiments herein makes referenceto the accompanying drawings, which show exemplary embodiments by way ofillustration and their best mode. While these exemplary embodiments aredescribed in sufficient detail to enable those skilled in the art topractice the disclosure, it should be understood that other embodimentsmay be realized and that logical, material, and mechanical changes maybe made without departing from the spirit and scope of the disclosure.Thus, the detailed description herein is presented for purposes ofillustration only and not of limitation. For example, the steps recitedin any of the method or process descriptions may be executed in anyorder and are not necessarily limited to the order presented.Furthermore, any reference to singular includes plural embodiments, andany reference to more than one component or step may include a singularembodiment or step. Also, any reference to attached, fixed, connected orthe like may include permanent, removable, temporary, partial, fulland/or any other possible attachment option. Additionally, any referenceto “without contact” (or similar phrases) may also include reducedcontact or minimal contact.

As used herein, “aft” refers to the direction associated with the tail(e.g., the back end) of an aircraft, or generally, to the direction ofexhaust of the gas turbine. As used herein, “forward” refers to thedirection associated with the nose (e.g., the front end) of an aircraft,or generally, to the direction of flight or motion.

As used herein, “outboard” may define an element or portion of anelement that is situated radially outer to or away from another,radially inward, element or portion of an element. Thus, an engine coremay be situated radially inboard of an inner fixed structure (“IFS”)and/or a fan casing, as described herein. As used herein, “inboard” maydefine the element or portion of the element that is situated radiallyinward in relation to an outboard element.

According to various embodiments, FIG. 1A illustrates a schematicsectional view of a gas turbine engine. Gas turbine engine 110 mayinclude core engine 120. Core air flow C flows through core engine 120and is expelled through exhaust outlet 118 surrounding exhaustcenterbody 122.

Core engine 120 drives a fan 114 arranged in a bypass flow path 124.Bypass air flow B, driven by the fan 114, flows in the aft directionthrough bypass flow path 124. At least a portion of bypass flow path 124may be defined by nacelle structure 112 and inner fixed structure (IFS)126. As is known, the general shape of IFS 126 is a surface ofrevolution around the engine axis, often with two bifurcation panels atthe six o'clock and the twelve o'clock position which extend radiallyoutward, and the IFS is often made from two generally mirror image clamshell halves that hinge together as part of the thrust reverserstructure. The radially-outboard surface of IFS 126 may be referred toas an inner flow surface 136 of the bypass flow path 124, and theradially-inboard surface of nacelle structure 112 may be referred to asan outer flow surface 138 of the bypass flow path 124. Fan case 132 maysurround fan 114. Fan case 132 may be housed within nacelle structure112.

With reference to FIG. 1B, intermediate case (IMC) 134 of the gasturbine engine 110 may be provided radially inward of fan case 132. Fancase 132 may provide mounting structure for securing gas turbine engine110 to a pylon 160. IMC 134 may is surrounded by nacelle structure 112.According to various embodiments, multiple guide vanes 116 may extendradially between fan case 132 and IMC 134.

Upper bifurcation 144 and lower bifurcation 142 are the spaces betweenopposite upper and lower bifurcation panels of IFS 126 clamshell halvesand may be used to accommodate the routing of engine components such aswires, air ducts, and fluids conduits.

Inner fixed structure 126 surrounds core engine 120 and helps definecore compartment 128. Various components may be provided in corecompartment 128 such as compressed air valves and/or a compressed airduct 130, for example. Compressed air duct 130 may carry hightemperature and high pressure compressed air for anti-icing purposes forseveral aircraft surfaces.

According to various embodiments, FIG. 2A illustrates a cross-sectionalview of the gas turbine engine taken from approximately along line 2-2in FIG. 1A and under normal operating conditions. Typically, the bypassflow path 124 will exert radially outward pressure on the inner flowsurface 136 and radially inward pressure on outer flow surface 138.

FIG. 2B illustrates a cross-sectional view of the gas turbine enginetaken along line 2-2 in FIG. 1A and under an overpressure event with aportion of the IFS in a deflected state. From time to time, a corecompartment 128 may experience more air pressure than it is typicallydesigned to handle (i.e., an overpressure event), for example in theevent that compressed air duct 130 bursts. An overpressure event tendsto exert a radially outward pressure upon the IFS 126. The pressureexerted radially outward upon the IFS 126 may be greater than thepressure exerted radially inward on the IFS from the bypass flow path124. In response, a portion of the IFS 126 may deflect radiallyoutwards. If the radially outward deflection of the leading edge of IFS126 is too great, it will begin to scoop the high velocity air in thebypass flow path 124, which may cause even greater deflections of IFS126 and a potential loss of structural integrity or permanent damage.

Accordingly, latch assemblies between the leading edge of the IFS andthe intermediate fan case may be provided to prevent the IFS fromdeflecting relative to an intermediate fan case in the event of anoverpressure event (e.g., a burst duct). However, during normaloperation, the IFS and the intermediate fan case may need to deflectrelative to one another. Therefore, the latch assemblies mustaccommodate these deflections. Preferably, the latch assemblies do nottake any load as a result of normal deflections between the IFS and theintermediate fan case, and are in waiting-fail-safe mode to only takeloads in case of more severe deflections caused by a burst duct.

With reference to FIG. 3A, an exemplary pin latch assembly in the closedposition is illustrated. According to various embodiments, pin latchassembly 300 may comprise a pin latch mount 312, a pin housing 308, apin retainer 314, and a pin 310. Pin latch mount 312 may be attached tothe radially inside surface of IMC bulkhead 334 near its trailing edge.Pin housing 308 may be attached to pin latch mount 312. Pin housing 308allows pin 310 to slide inside of it. Pin retainer 314 may be attachedto the radially inside surface of IFS 126 near its leading edge. Pinretainer 314 may comprise a slotted hole 315 configured to allow pin 310to pass through slotted hole 315. Pin 310 may be configured toreciprocate within pin housing 308 between an extended and retractedposition. The extended position may be defined as a position where pin310 is extended from pin housing 308 such that at least a portion of pin310 may pass into slotted hole 315. The retracted position may bedefined as a position where pin 310 is retracted inside of pin housing308. The pin latch assembly 300 is capable of an unlatched positionwhere the pin 310 is retracted and not located inside of slot 315, and alatched position where pin 310 is extended and located inside of slot315.

According to various embodiments, pin latch mount 312 may be attached toIMC bulkhead 334 via fasteners such as a threaded pin/threaded fastenersuch as that sold under the trademark HI-LOK, for example. According tovarious embodiments, pin retainer 314 may be attached to IFS 126 viafasteners. According to various embodiments, pin housing 308 may beattached to pin latch mount 312 via welding or fasteners. According tovarious embodiments, pin latch mount 312, pin housing 308, pin retainer314, and pin 310 may comprise of any metal, such as stainless steel oraluminum, for example.

When pin latch assembly 300 is latched, a portion of pin 310 has passedinto slotted hole 315, and a waiting-fail-safe load path may be createdbetween IFS 126 and IMC bulkhead 334 by, for example, sizing pin 310 sothat its diameter is less than the width of slotted hole 315. Pin 310can move inside of slotted hole 315 to accommodate normal deflectionsbetween IMC bulkhead 334 and IFS 126 without taking load.

During an overpressure event, IFS 126 may deflect radially outward,causing pin 310 to contact pin retainer 314. In this manner, pin latchassembly 300 may arrest any additional IFS deflection by creating a loadpath which may travel from IFS 126, through pin retainer 314, throughpin 310, through pin housing 308, through pin latch mount 312, and intoIMC bulkhead 334. Accordingly, pin latch assembly 300 may preventdamaging, excessive IFS deflection during an overpressure event.Deflections of the IFS 126 leading edge may be the most important tocontrol in order to ensuring that a scooping condition does not occur,and pin latch assembly 300, positioned between the leading edge of IFS126 and the trailing edge of IMC bulkhead 334, is well positioned toarrest such deflections.

With reference to FIG. 3C and FIG. 3D, a side view of exemplary pinlatch assembly 300 in the latched and unlatched positions, respectively,is illustrated, in accordance with various embodiments. An actuatingdevice, such as cable 311, may be coupled to pin 310 to cause pin 310 totranslate with respect to pin retainer 314. Pin 310 may be attached tocable 311 via a coupler such as a clevis, for example. Pin 310 may beattached to cable 311 via weld, solder, or any other suitable method.According to various embodiments, pin 310 and cable 311 may beintegrally manufactured. Though shown as cable 311, any suitableactuating device is contemplated herein to cause pin 310 to translatewith respect to pin retainer 314.

In accordance with various embodiments, FIG. 5A illustrates a latchhandle assembly with cable placement. A cable sleeve 306 may be providedto enclose cable 311. Cable sleeve 306 may be attached to and extendfrom pin latch mount 312 or pin housing 308 on one end to a latch handle542 on the other end to form a flexible cable actuation system, as isknown. As illustrated by FIG. 5A, cable 311 may be routed from pin latchassembly 300 (with reference to FIG. 3A) along the radially-inwardsurface of IMC bulkhead 334, then through the bulkhead and through ahollow portion of one of guide vanes 116 and through the fan case, andfinally to latch handle 542, in accordance with various embodiments.Latch handle 542 may be attached to fan case 132 (with reference to FIG.1B). Latch handle 542 permits latching and unlatching of pin latchassembly 300 remotely (with reference to FIG. 3A).

With reference to FIG. 5B, when latch handle 542 is opened, cable 311may be tensioned, causing the pin 310 to retract and the pin latchassembly 300 to unlatch. When latch handle 542 is closed, cable 311 maybe compressed causing the pin latch assembly 300 to latch.

A balking device is provided to prevent a fan cowl 540 from closing whenlatch handle 542 is opened and pin latch assembly 300 is unlatched.Balking device 546 may be a tab which extends radially inward from fancowl 540. When fan cowl 540 moves toward its closed position, balkingdevice 546 will contact an open latch handle 542 and the fan cowl willnot close further. This helps ensure that the latch handle 542 is movedto the closed position and the pin latch assembly 300 is latched beforethe fan cowl is closed.

In addition to pin latch mount 312 being attached to IMC bulkhead 334and pin retainer 314 being attached to IFS 126, pin latch mount 312 andpin retainer 314 may be located in inverse locations. In such anembodiment, the cable 311 could be routed along the radially innersurface of the IFS 126 to a handle located in the lower bifurcation 142.

In addition to the pin latch assembly 300, a cam latch assembly isdisclosed. With reference to FIG. 4A, FIG. 4B, FIG. 4C and FIG. 4D, aview of an exemplary cam latch assembly in the closed position and openposition respectively is illustrated, in accordance with variousembodiments. According to various embodiments, cam latch assembly 400may comprise a cam latch mount 412, a cam retainer 414, and a cam 410.Cam latch mount 412 may be attached to a radially inner surface of IMCbulkhead 334. Cam retainer 414 may be attached to a radially innersurface (opposite flow surface 136) of IFS 126. Cam retainer 414 maycomprise an opening 415 configured to allow cam 410 to position itselfwithin opening 415 (also referred to as a channel) when the cam latchassembly is latched. Cam 410 may be attached to cam latch mount 412 viapivoting pin 422. Cam 410 may be configured to pivot about pivoting pin422 during unlatching and latching.

According to various embodiments, cam 410 may be configured to pivot inand out opening 415 when pivoting between a latched and unlatchedposition respectively. A latched position may be defined as a positionwhere cam 410 is pivoted such that at least a portion of cam 410 ispositioned in opening 415. An unlatched position may be defined as aposition where cam 410 is pivoted such that no part of cam 410 ispositioned in opening 415. Opening 415 may be defined as having a depth491 and a width 493 as illustrated in FIG. 4B. The depth 491 and width493 are selected to allow normal deflections between the IMC bulkhead334 and the IFS 126.

According to various embodiments, cam 410 may rotate about pivoting pin422 in response to a pushing or pulling force generated via cable 311.Cable 311 may be attached to cam 410 via fastener 407. Fastener 407 maybe a clevis fastener or any other type of suitable fastener. Fastenerpin 424 may be configured to attach fastener 407 to cam 410.Accordingly, cam 410 may pivot about fastener pin 424 during opening andclosing of cam latch assembly 400.

As described above, a cable sleeve 306 may be provided to enclose cable311 and form a flexible cable actuation system. Cable sleeve 306 mayattach to on one end and extend from the cam latch mount 412 and attachto a handle assembly on the other end. The cable may be routed throughone of the guide vanes 116 as previously described.

According to various embodiments, in response to latch handle 542 (FIG.5A) being actuated from a closed to an open position, a tension forcemay be applied to cable 311, causing cam 410 to pivot about pivoting pin422 and pivot out of opening 415, into an unlatched position. Accordingto various embodiments, in response to latch handle 542 (FIG. 5A) beingactuated from an open to a closed position, a compressive force may beapplied to cable 311, causing cam 410 to pivot about pivoting pin 422and pivot into opening 415 into a latched position.

As described above with respect to the pin latch assembly, duringtypical operating conditions, cam 410 does not contact cam latch mount412. Cam 410 may deflect with IFS 126 and with respect to IMC bulkhead334, without contacting cam latch mount 412. In that regard, cam latchassembly 400 provides a waiting-fail-safe load path between IFS 126 andIMC bulkhead 334.

According to various embodiments, during an overpressure event, the IFS126 may deflect radially outwards. In response, provided cam latchassembly 400 is in a closed position, cam 410 may contact cam latchmount 412. In this manner, cam latch assembly 400 may prevent IFSdeflection by creating a load path which may travel from IFS 126,through cam 410, through cam latch mount 412, and into IMC bulkhead 334.Accordingly, cam latch assembly 400 may prevent IFS deflection andmaintain IFS 126 integrity during a burst event.

In addition to cam latch mount 412 being attached to IMC bulkhead 334and cam retainer 414 being attached to IFS 126, cam latch mount 412 andcam retainer 414 may be located in inverse locations. In such anembodiment, the cable 311 could be routed along the radially innersurface of the IFS 126 to a handle located in the lower bifurcation 142.

Benefits, other advantages, and solutions to problems have beendescribed herein with regard to specific embodiments. Furthermore, theconnecting lines shown in the various figures contained herein areintended to represent exemplary functional relationships and/or physicalcouplings between the various elements. It should be noted that manyalternative or additional functional relationships or physicalconnections may be present in a practical system. However, the benefits,advantages, solutions to problems, and any elements that may cause anybenefit, advantage, or solution to occur or become more pronounced arenot to be construed as critical, required, or essential features orelements of the disclosed embodiments. The scope of the claimedembodiments is accordingly to be limited by nothing other than theappended claims, in which reference to an element in the singular is notintended to mean “one and only one” unless explicitly so stated, butrather “one or more.” Moreover, where a phrase similar to “at least oneof A, B, or C” is used in the claims, it is intended that the phrase beinterpreted to mean that A alone may be present in an embodiment, Balone may be present in an embodiment, C alone may be present in anembodiment, or that any combination of the elements A, B and C may bepresent in a single embodiment; for example, A and B, A and C, B and C,or A and B and C. Different cross-hatching is used throughout thefigures to denote different parts but not necessarily to denote the sameor different materials.

Systems, methods and apparatus are provided herein. In the detaileddescription herein, references to “one embodiment”, “an embodiment”, “anexample embodiment”, etc., indicate that the embodiment described mayinclude a particular feature, structure, or characteristic, but everyembodiment may not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same embodiment. Further, when a particular feature,structure, or characteristic is described in connection with anembodiment, it is submitted that it is within the knowledge of oneskilled in the art to affect such feature, structure, or characteristicin connection with other embodiments whether or not explicitlydescribed. After reading the description, it will be apparent to oneskilled in the relevant art(s) how to implement the disclosure inalternative embodiments.

Furthermore, no element, component, or method step in the presentdisclosure is intended to be dedicated to the public regardless ofwhether the element, component, or method step is explicitly recited inthe claims. No claim element herein is to be construed under theprovisions of 35 U.S.C. § 112(f), unless the element is expresslyrecited using the phrase “means for.” As used herein, the terms“comprises”, “comprising”, or any other variation thereof, are intendedto cover a non-exclusive inclusion, such that a process, method,article, or apparatus that comprises a list of elements does not includeonly those elements but may include other elements not expressly listedor inherent to such process, method, article, or apparatus.

We claim:
 1. A latch assembly located between a leading edge of an innerfixed structure (IFS) and an engine case comprising: a latch mount; acam retainer including an opening; a cam attached to the latch mount viaa pivoting pin, at least a portion of the cam positioned in the opening;a handle; a receiver, wherein the latch assembly is configured to be ina latched position when the cam is located within the receiver, whereinthe receiver and the cam comprise a waiting-fail-safe load path when inthe latched position, wherein the handle is coupled to a fan case,wherein the handle is coupled to the cam via a flexible cable, whereinthe flexible cable is routed through a guide vane, the guide vane beinglocated between the engine case and the fan case.
 2. The latch assemblyof claim 1, wherein the cam is configured to rotate about a pivotdefined by the pivoting pin.
 3. A latch assembly located between aleading edge of an inner fixed structure (IFS) and an engine casecomprising: a latch mount; a cam retainer including an opening; a camattached to the latch mount via a pivoting pin, at least a portion ofthe cam positioned in the opening; a handle; a receiver, wherein thelatch assembly is configured to be in a latched position when the cam islocated within the receiver, wherein the receiver and the cam comprise awaiting-fail-safe load path when in the latched position, wherein thecam is remotely actuated by a flexible cable, wherein the flexible cableis toured through a guide vane between the engine case and a fan case.4. The latch assembly of claim 3, wherein the cam is configured torotate about a pivot defined by the pivoting pin.